1. Field of Invention
The present invention relates to eddy current monitoring and in particular a probe for eddy current monitoring of boiler tubes.
2. Description of Related Art
The process of testing metal for failure with eddy current probes is well known in the art. Further, the use of this technology in the field of boiler tube testing is also well known. Within the non-destructive inspection industry, clearly identifying and classifying mater anomalies is critical to reliability and safety of the devices under inspection. The identification of characteristics such as fatigue cracks, stress corrosion cracking (SCC), intra-granular attack (IGA), pitting, fretting and other material or dimensional profile changes can have a catastrophic effect on material or part integrity.
Traditional eddy current testing (ECT) has been the dominant tool for studying the integrity of conductive materials. The most predominant type of ECT probe is the bobbin probe. Due to the geometry of the stimulating coil and the resultant eddy current field morphology, a bobbin probe has far higher probability of detection for axial flaws than circumferential flaws.
Current systems use complex multi-inductive coil probes with application specific integrated circuit drive electronics mounted at the probe head to interface with the coils to perform multiplexing. This arrangement allows a full inspection of axial and circumferential flaws, but requires that power be supplied to the sensor head for the electronics. The need for power at the head and associated electronics can negatively impact reliability due to delivery induced electrical failures and device failures.
There remains a need for a simple probe for sensing both axial and circumferential tube flaws that does not require a powered head.
All references cited herein are incorporated herein by reference in their entireties.